2013 Posts

Dust Sucker

Thien baffle - top view
Imagine air swirling around!

Why would anyone make a vacuum out of wood, you ask? I have no idea. But I'm doing it anyway.

Looking around the internet, I saw that Mattathias, of woodgears.ca, had built a dust collector out of wood. It used a Thien baffle for its filtration, and depended only slightly on filters.

Frustrated with the ever-clogging filters of shop vacs, I've wanted to make a cyclonic separator for a while. When I saw his unit - a quiet, standalone separator, I decided to build one.

Wooden Lock: Finishing

School starts, and I'm busy again. I have all sorts of cool things to write about, and not enough time to do so. But I'm on top of homework, so here's the conclusion to the combination lock saga!

I wish I could describe the measurements better, but that's a job for engineering drawings, not text. I'll see about making some proper drawings soon.

After deciding on about half the dimensions, we started cutting. The tumblers and washers were first, then I popped a few dowels onto the lathe to turn them down a bit. When I finished, the tumblers spun smoothly on the central shaft.

We assembled the core of the lock with brass screws. First, we slid a washer onto the central shaft, then a tumbler, another washer, and so on until it was built up. After a quick test to make sure everything interfaced well, we screwed the washers into the central dowel with brass screws, being careful to keep the tumblers under a bit of pressure (to prevent wobble and slippage).

Extruder woes

Just a quick update. I finished reassembling the extruder last week. Compared to the old raygun, the new one has a few notable changes. The heat sink's closer to the heater block, to try and reduce the coefficient of friction between the walls and molten plastic. The leads of the resistor and the thermistor are insulated within concrete, so they won't short to the heater block. The cooling fan's fastened on better. Most notably, the hot end of the hot end is now swaddled in fiberglass - bona fide insulation.

On the bright side, the hot end performs like a champ. Only the lower two washers of the heat sink were warm, and the heater block came up to temperature with much more authority than usual.

Unfortunately, it still doesn't work. I tried an extrusion yesterday, to no avail. The printer produced a few sickly-looking brown blobs of plastic (my filament's white), but refused to extrude filament.

Hobbed Bolt

Wow. It's been a while since I worked on this. In fact, the whole thing's a bit dusty. I'll give it a good cleaning before I start printing.

Towards the end of last summer, I realized that the old hobbed bolt - the thing that drives filament into the hot end - had worn out. Hobbing is threading on the bolt that grabs the filament and drives it into the hot end. The printer doesn't print so well when it can't push filament.

Recently, I bought another hobbed bolt, and it just arrived!

When I went to swap it in, I found the hobbing (notches) were in the wrong place, and ran to the engineering building for some spacers.

Next problem: with the spacers in place, the gearbox doesn't line up anymore. The big gear stands off too far from the drive gear. So, I popped off the stepper motor and pried at the gear with a screwdriver. (Fun fact: the right tools make anything easier. I don't have the right tools.)

Now to power it up! Steppers - check. USB - check. Power - check. Power supply online. Serial connection up. Temperature probes working. And the Z axis takes a dive.

Not working yet, but it's still alive. Cool.

The X axis is fine, as is Y. Z needed to be plugged back in; one of the connectors had worked loose. And with that, the printer was back. Time to figure out the hot end!

I took apart the hot end, which had fallen apart in transit from home to school, then reassembled it. I also put stronger springs into the cold end - should provide more driving force.

Problem, though. The pocket holes for nuts in the cold end are smaller than the nuts themselves. I guess the saying's true: when all you have is a dremel, everything looks like it needs a good grinding.

So, I ground the holes bigger. What can I say - it worked!

The hot end, cold end, and axes are all together. Time for some testing. And then, god willing, extrusion!

Facebook Notifications

Yesterday, I set up an account with Facebook. I'm not especially fond of the service, but my girlfriend's abroad, with metered internet, and wants to send me pictures. Facebook lets her upload once, and share many times. I'm also under pressure from other organizations to have a profile there. So I caved and set it up.

One of my fears of the service is spending too much time there, or going often to check that I haven't missed any important messages. I know that there are clients for Macintosh that will pull Facebook notifications to the desktop, but couldn't find a parallel for Linux. There are a few clients, but they're either processing-heavy or just broken.

Resurrection

Last year, before I left for college, my parents bought me a Lenovo SL510. I love the computer - it's passably rugged, ugly as sin, its bezel makes a great drawing surface, and it runs Linux like a champ. (I used to dual-boot, but that's neither here nor there.)

In the back right corner, the laptop has a plug for the power adapter. Over the summer, the power plug broke. The adapter connects to the board with some wire; that remained intact. But the plug broke loose from the computer's chassis and started wandering around inside. Most of the time, it'd move a few millimeters, and I'd drag it back to the proper slot, then plug in the power. Last week, it did something different.

Wooden Lock: Design

Last time, I described how a combination lock worked. This article describes how the concept is implemented in wood, and our early design process. We started our design by foraging for stuff surveying our assets. We based our design on the large sheet of ¼" plywood, and 3/16" and ½" diameter dowels we found. Foraging Looking for interesting tools netted us hole saws (ranging from ½" to 2" internal diameter).

Wooden Lock: Information

Recently, I made a combination lock out of wood. I'll be describing it in a series of articles because to save you, dear reader, from a numbing fifteen hundred word epic.

So, what in the world would posses me to make a combination lock out of wood? Well, some time ago, I saw a working model of a combination lock on woodgears.ca, looked it over, thought it was cool, and stashed the idea in the back of my mind with fulgurates and sous vide.

Months later, I was looking for winter break projects, and I thought of this lock. Helen & I decided to build a pair of them, scaled down from the version that Matthias built on woodgears. Why?

XFCE Workspace Background, redux

As I was writing yesterday, I realized that my code was sloppy, particular to my needs, and nearly unusable. I refactored the script to be more intuitive. When called, the script switches to the desktop specified by the first argument (it's zero-indexed), drops in a new background image list, and updates the background. The background changes a few hundred ms after switching, but it's good enough for me.

Here are directions for using it:

XFCE Workspace Desktop Rotation

Linux offers a wonderful feature called workspaces: I can have an arbitrary number of desktops, and arrange windows however I want. One could have a music player running fullscreen, another can run GIMP, and a third could have a tutorial. Keyboard shortcuts let me jump between workspaces. In effect, multiple workspaces give me four screens for the price of one.

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